Perhaps the most important such limit is the fact that the Court has no power to enforce its decisions. When the Court hands down a decision, the executive branch must enforce it. If the executive drags its feet on enforcing a decision, the decision has little weight. This means that the Court must limit itself to decisions that it can hope will be enforced.
Another very important limit is the fact that the Court can only rule on cases brought before it. It cannot go out and make policy on its own. The Court cannot, for example, put in place its own health care plan or its own tax policy. It can only rule on specific issues that come before it.